Children in sync: exploring how interpersonal synchrony experience induces cooperation between child peers.

Synchronous interpersonal movements induce positive prosocial behaviors in adults and children. The processes that underlie this are debated. Here, we investigate the extent to which visual cues available during synchrony experience-particularly shared facial expressions and mutual eye contact-are necessary. Pairs of same-sex 4-year-olds (N = 216 children; 50% girls; 81% white) from the US were randomly assigned to synchronized versus asynchronized swinging experience. Access to visual information was experimentally manipulated by using a transparent versus translucent barrier between the children. The translucent barrier acted as a visual filter preventing children from monitoring facial cues while still enabling them to see whether the partner was swinging in synchrony. After the swinging experience, all pairs of children were administered the same tests of cooperation. The children administered synchronous movement performed better on the cooperation tasks, and there was no significant difference as a function of barrier transparency. This suggests that the positive effects of synchrony do not require visual resolution of the partner's social-emotional facial cues. These findings advance our understanding about factors contributing to synchrony-induced cooperation between children.